Ovaries become immune organs after menopause: mouse study
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- Francesca Duncan at Northwestern University and colleagues analysed ovaries from mice aged 2, 18, and 24 months, finding that genes linked to inflammation and immune activity became increasingly active with age while reproductive and hormone-producing genes (including estradiol) were downregulated.
- The team confirmed the expected age-related changes — loss of egg-producing follicles and increased scarring — but also documented rising numbers of T cells and macrophages infiltrating the ovaries, which Duncan called an identity shift rather than the organ becoming 'an immune superpower.'
- A companion March study by Duncan's group, not yet peer reviewed, examined protein composition in ovaries of post-menopausal women aged 50 to 75 and found molecular signatures changed dramatically across decades, contradicting the assumption that the organ is stagnant after reproduction ends.
- Diana Laird at the University of California, San Francisco, said the mouse findings likely translate to humans given shared features like fibrosis and increased nerve distribution, and called for 'detailed and functional studies on the cellular and molecular components of the post-reproductive ovary.'
- Laird added the results reinforce growing evidence that ovarian immune changes may drive the post-menopausal inflammation linked to conditions like rheumatoid arthritis, challenging the current practice of leaving healthy ovaries in place after menopause for their androgen production.
- Duncan speculated the immune shift may have been evolutionarily advantageous when few humans survived to old age, but could now contribute to chronic low-grade 'inflammaging' and even autoimmune conditions in modern lifespans.
- The study was published in Molecular Human Reproduction (DOI: 10.1093/molehr/gaag038), and the researchers stressed further work is needed to determine whether the infiltrated ovaries are actually releasing inflammatory signalling molecules into the body.
Why it matters: Roughly half the population experiences menopause, and post-menopausal women face elevated rates of autoimmune and inflammatory conditions — yet the ovary's role beyond reproduction has been dismissed. If the organ is actively driving systemic inflammation, it could reshape how clinicians think about ovary removal versus preservation after menopause and open new targets for treating age-related immune disorders in women.
